L8T Factory-verified

GMC · Regular Production Option

Engine, 6.6L V8, direct injection, variable valve timing, gasoline

Years 2020–27 Models 2 Factory citations 14

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Also documented for Chevrolet

Documented applications

Savana — GMT610 (2003–2027)

2022–2027 Factory-verified

the 2025–2027 guides give 401 hp at 5200 rpm and 464 lb-ft at 4000 rpm and read it Engine, 6.6L V8; the 2022–2026 upfitter lists read engine, gas, 8 cylinder, 6.6L, SIDI, VVT, cast iron; S: Cutaway 2WT (2025–2026), Cutaway TG33803, Cutaway TG33903 (2025–2026); O: Cargo 1WT, Cutaway TG33503, Passenger 1LS, Passenger 1LT

GM factory document — 2022 chevrolet 22 express savana electrical body builder sm en us 2021oct12, p.13.
GM factory document — 2025 chevrolet my25 express savana electrical bbm, p.12.
GM factory document — 2025 gmc savana cargo fleet order guide, p.31.
GM factory document — 2025 gmc savana cutaway fleet order guide, p.39.
GM factory document — 2025 gmc savana passenger fleet order guide, p.23.
GM factory document — 2026 chevrolet my26 express savana electrical bbm, p.12.
GM factory document — 2026 gmc savana cargo fleet order guide, p.34.
GM factory document — 2026 gmc savana cutaway fleet order guide, p.43.
GM factory document — 2026 gmc savana passenger fleet order guide, p.25.
GM factory document — 2027 gmc savana cargo fleet order guide, p.30.
GM factory document — 2027 gmc savana cutaway fleet order guide, p.21.
GM factory document — 2027 gmc savana passenger fleet order guide, p.23.

Sierra HD — T1XX (2020–2027)

2020–2026 Factory-verified

401 hp (299 kW) at 5200 rpm and 464 lb-ft (629 N-m) at 4000 rpm; 2020 to 2024: GM Authority Sierra HD model-year pages

GM factory document — 2025 gmc sierra 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2026 gmc sierra 2500 hd retail and fleet fleet order guide rpo codes, p.1.

This page aggregates every documented appearance of L8T in the GMC reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.